Method of shortening multiple-image scanning duration

ABSTRACT

A method of shortening multiple image-scanning duration including setting the scanning parameters of each images in a pre-scanning operation, categorizing the images into groups, assigning images belonging to the same group to a scanning region and finally initializing the scanning operation.

BACKGROUND OF THE INVENTION

[0001] 1. Field of Invention

[0002] The present invention relates to a method of scanning multipleimages. More particularly, the present invention relates to a method forshortening multiple-image scanning duration.

[0003] 2. Description of Related Art

[0004] In general, a scanner has a scanning head over a scanningsurface. The scanning head is driven by a stepping motor to scan adocument. FIG. 1 is a schematic diagram showing the positions of ascanning head 102 driven by a stepper into performing a multiple imagescanning operation. As shown in FIG. 1, a multiple of scanning documentsA to G is placed over a scanning platform. To carry out an imagescanning, the scanning head 102 is driven from an initial position downto the edge line ‘a’ of image A. Image A is scanned until the edge linec of image A is reached. However, during scanning, the scanning head 102reaches the edge line b of image B first. Consequently, after completescanning of image A, the scanning head 102 is driven by the stepper backto edge line b before image B can be scanned. By repeating theaforementioned scanning steps, all images on the scanning platform arescanned. The pointed arrows on the left hand side of FIG. 1 indicate thedirection of movement of the scanning head 102 driven by the stepper. Inother words, the arrows show the stepping movement of the scanning head102 for a complete scanning of images A˜G.

[0005] In a multiple image scanning operation, if a scanning linesection is within two or more images, backtracking of the scanning headis required. For example, image A and image B contains a common scanningline section and the scanning head needs to backtrack after scanningimage A before scanning image B. Similarly, image B and image C have acommon scanning line section and the scanning head needs to backtrackafter scanning image B before scanning image C.

[0006] During normal scanning, the stepper motor must shuttle back andforth to bring the scanning head 102 into position. Hence, a lot of timeis wasted in the conventional method to move the scanning head overoverlapping scanning line sections.

SUMMARY OF THE INVENTION

[0007] Accordingly, one object of the present invention is to provide amethod for shortening multiple-image scanning duration and reducingnon-performing movement of scanning head.

[0008] To achieve these and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, theinvention provides a method of shortening multiple-image scanningduration. The method includes the following steps. In a pre-scanningstage, scanning parameters for each scan image are set. A most suitablecategorization method is used to classify the images. Similar types ofscan images are grouped together under the same scanning region.Finally, scanning is initialized.

[0009] The categorization method includes the following criteria. Imagesthat contain a common scanning line section are put in a first category.Images that are within a preset number of scanning stops are put in asecond category. Images that are within a resolution range are put in athird category. In addition, images that fit user-defined parameters areput in a fourth category. Images may be classified using just one typeor more than one type of image categorization. The purpose of dividingimages into different categories is to complete image scanning in theshortest scanning path.

[0010] In brief, this invention utilizes a pre-scanning operation toclassify a set of images into different categories before actuallyconducting a scanning operation. Since the scanning head driven by thestepper motor is able to traverse the shortest possible path to completethe scanning, overlapping forward/backward movement is minimized. Insome cases, scanning can be completed in a single forward or backwardmovement instead of a forward and backward movement, further reducingscanning time for scanning multiple images.

[0011] It is to be understood that both the foregoing generaldescription and the following detailed description are exemplary, andare intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention. In the drawings,

[0013]FIG. 1 is a schematic diagram showing the positions of a scanninghead 102 driven by a stepper into performing a multiple image scanningoperation;

[0014]FIG. 2 is a flow-chart showing the steps for scanning multipleimages according to this invention;

[0015]FIG. 3 is a flow-chart showing the steps for categorizing imagesand setting up scanning regions according to this invention; and

[0016]FIG. 4 is a schematic diagram showing the resultant form afterimage categorization and image grouping according to this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Reference will now be made in detail to the present preferredembodiments of the invention, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numbers areused in the drawings and the description to refer to the same or likeparts.

[0018]FIG. 2 is a flow chart showing the steps for scanning multipleimages according to this invention. The method according to thisinvention includes the following steps. First, a pre-scanning operationis conducted to pick up those images that require scanning and set thescanning parameters of those images (in step 202). The scanningparameters include image resolution and quantity of image data. Theimages are categorized (in step 204) and images in the same category areset inside the same scanning region (in step 206). A stepper motordrives a scanning head to initiate a scanning operation (in step 208).The scanning operation is checked to determine if all scanning regionsare already scanned (in step 210). If all scanning regions are scanned,images within a scanning region are separated out (in step 212) beforethe end of the scanning operation.

[0019]FIG. 3 is a flow chart showing the steps for categorizing images(in step 204) and setting up scanning regions (in step 206) according tothis invention. First, a first image is selected to be acontrast-scanning region (in step 302). A comparison between anotherselected image and the contrast-scanning region (in step 304) isconducted. The image is inspected to determine if there is any commonscan line section with the contrast-scanning region (in step 306). Ifthere is such a common scan line section, the two are integratedtogether to form a new contrast-scanning region and continue to inspectwhether there are any more images not yet selected (in step 308). On theother hand, if there is no common scan line section, thecontrast-scanning region excluding the selected image is set as ascanning region (in step 310) and the selected image is chosen as a newcontrast-scanning region (in step 312). The aforementioned process isrepeated if some images are still pending selection (in step 314). Inother words, if some images remain to be selected, control is returnedto image selection and comparison with the contrast-scanning region step(step 304). If all images have been selected, image categorization andscanning region setting is complete.

[0020] The following is an example of the steps 204 and 206 in FIG. 2for putting images into different regions. In the example, assume imagesare categorized according to whether the image contains a commonscanning line section. Two or more images have a common scanning linesection if a scanning line passes through all those images.

[0021]FIG. 4 is a schematic diagram showing the resultant form afterimage categorization and image grouping according to this invention. Asshown in FIG. 4, images A, B, C, D, E, F and G need to be categorizedaccording to whether they have any common scanning line section. A firstimage such as A is selected to be a contrast-scanning region (in step302). A second image B is selected to compare with the contrast-scanningregion (image A) (in step 304). The selected image B and thecontrast-scanning region have a common scanning line section (in step306). Image A and image B are integrated together to form a newcontrast-scanning region (in step 308). Since there are some imagesremain to be selected such as image C (in step 314), control returns tostep 304 again. Image C is compared with the new contrast-scanningregion (integration of image A and B) to check if there is any commonscanning line section (in step 306). If there is, image C is combinedwith the old contrast-scanning region to produce a new contrast-scanningregion (in step 308). The above procedure is repeated. It is notdifficult to see that image pairs A-B, B-C, C-D, B-D all contains commonscanning-line sections. Hence, in step 310, images A, B, C and D can begrouped together to form a scanning region 402.

[0022] Before images A, B, C and D are combined together into a scanningregion 402, step 306 needs to be executed. In step 306, it is determinedthat image E has no common scan line section with any one of the imagesA, B, C and D. Hence, in step 310, the contrast-scanning region thatexcludes image B becomes the scanning region 402. In step 312, image Eis chosen to be the new contrast-scanning region.

[0023] Steps 304 to 314 are repeated until all images are categorized.By a similar procedure, images E and F are set inside the same scanningregion 404 while image G is independently set inside the scanning region406.

[0024] In step 306, this invention also provides procedures forcategorizing the degree of resolution of the images. If the resolutionof a number of images falls within a definite range, these images may begrouped together inside a scanning region.

[0025] Furthermore, in step 306, this invention also provides proceduresfor categorizing the number of scanning stops after image integrationinto groups each having a preset range. In other words, if the number ofscanning stops after image integration falls within a defined range, theintegrated images are grouped together inside a scanning region.

[0026] When the stepper motor drives the scanning head to perform ascanning operation, data are transferred to an image buffer. After thedata buffer is completely filled, the stepper motor will stop until alldata within the buffer are transferred elsewhere. This process isrepeated until all scanning regions are scanned and data transferred.The number of scanning stops refers to the number of times the steppermotor needs to be stopped.

[0027] Utilizing a preset stop-scanning number as a means ofcategorization refers to estimating whether the number of scanning stopsof the images forming the contrast-scanning region is within the presetstop-scanning range in the pre-scanning operation. If the number iswithin range, the images of the contrast-scanning region are set insidethe same scanning region and vice versa.

[0028] In addition, in step 306, this invention also permits a user toset up user-defined parameters to categorize the images. Images havingthe same user-defined parameters are grouped together inside a scanningregion. In other words, images can be arbitrarily categorized and thescanning region for a particular set of images can be arbitrarilyassigned.

[0029] In summary, images are categorized according to whether theimages have a common scanning line section, whether the images fallwithin a resolution range, whether the number of scanning stops duringan image scanning operation is within a preset number or whether theimage belongs to a set of user-defined parameters. Besides using any oneof the aforementioned categorization methods, images may be categorizedaccording to any combination of the methods. For example, resolution andthe number of scanning stops can be used as criteria for categorizingthe images in step 306.

[0030] After proper categorization of images and assignment of scanningregions, the stepper motor is able to drive the scanning head along anoptimal or shortest path during a scanning operation with fewoverlapping forward/backward movements. In some cases, scanning can becompleted in a single forward or backward movement instead of a forwardand backward movement, further reducing scanning time for scanningmultiple images. In short, this invention is able to reduce scanningpath length and scanning time.

[0031] It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentinvention without departing from the scope or spirit of the invention.In view of the foregoing, it is intended that the present inventioncover modifications and variations of this invention provided they fallwithin the scope of the following claims and their equivalents.

What is claimed is:
 1. A method of shortening multiple image scanningduration, comprising the steps of: setting the scanning parameters ofeach image in a pre-scanning operation; classifying the images intogroups according to a categorization method; assigning all imagesbelonging to the same group to a scanning region; and initializing thescanning operation.
 2. The method of claim 1, wherein after scanning allscanning regions, images belonging to the same scanning region aregrouped together.
 3. The method of claim 1, wherein the step ofassigning images belonging to the same group to the same scanning regionfurther includes the sub-steps of: selecting out a first unprocessedimage to serve as a contrast-scanning region; selecting the next in lineunprocessed image and comparing with the contrast-scanning region;determining if the unprocessed image and the contrast-scanning regionhas a common scanning line section; integrating the selected unprocessedimage and the contrast-scanning region to become a new contrast scanningregion if the unprocessed image and the original contrast-scanningregion has a common scanning line section; assigning thecontrast-scanning region to be a scanning region if the selectedunprocessed image and the contrast-scanning region has no commonscanning line section; and repeating the aforementioned steps until allimages are processed.
 4. The method of claim 1, wherein the scanningparameters includes the resolution of the image and the data quantity ofthe image.
 5. The method of claim 1, wherein the categorization methodincludes grouping all images containing a common scanning line sectiontogether.
 6. The method of claim 1, wherein the categorization methodincludes grouping all images having a number of scanning stops within apreset scanning stop range together.
 7. The method of claim 1, whereinthe categorization method includes grouping all images having aresolution within a preset resolution range together.
 8. The method ofclaim 1, wherein the categorization method includes grouping all imageshaving user-defined properties together.
 9. The method of claim 1,wherein the categorization method further includes grouping the imagestogether according to common scanning line sections, preset scanningstop number ranges, image resolution ranges, user-defined properties orvarious combinations of the above.